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A question about DIN standards and objective parfocal distance

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#1 rzgp33

rzgp33

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Posted 04 December 2019 - 07:42 PM

Hello all

 

I have a question about mixing a matching objectives an eyepieces.

I have a few old Olympus microscopes in the 1950-70s era

 

I have just purchased a nice BHB Olympus microscope. Images though it look ok, but not great. I still have clean it up, its very dusty.

 

The BHB is a lower end research grade DIN scope with tube length of 160mm

 

Looking at Alan Woods excellent site

 

http://www.alanwood.net/

 

I see that it was designed for objectives with a parfocal distance of 36.65mm

 

However the objectives and eyepiece on the scope look to be for a BH-2 which has a parfocal distance of 45mm

 

eyepieces are 2x WHK 10x/20 L, NFK 3.3x photo eyepiece

objectives are DPlan 10-40 160/0.17

 

My reading of the standards is that the 160mm tube length is from the objective mounting flange to the eyepiece flange.

So am I right in thinking that as long as I match the 45mm objective with the WHK eyepieces (i.e they way it came) then all will be well?

 

Or is there something in the design of the prisms of the BHB that makes it necessary to obtain the 36.65mm objectives to get the best performance?

 

i.e should I be looking for a BH-2 to match the objectives I have, or a set of 36.65mm objectives/eyepieces, or can I sit as is.

 

The images are fine visually, but I want to set it up as a photomicroscopy platform and so want to get it right.

 

Brian



#2 Microscopy

Microscopy

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Posted 28 December 2019 - 05:16 AM

Both the Olympus BH and BH2 series microscopes were designed as 160 mm tube length microscopes and 160 mm = 160 mm. IMHO there's no reason why more recent 45mm objectives shouldn't fit.

The other way around would be more difficult, as the BH2 series can't accomodate the older, shorter objectives due to lack of travel of the focussing mechanism. I suppose that's a problem that can be solved, but I'm not sure. I know it's not that hard to solve in f.e. the grey Zeiss Standard microscopes.

 


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